• KOREAN JOURNAL OF CROP SCIENCE
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• v.32 no.4
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• pp.436-442
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• 1987

The variations of the anther and pistil length of some rice cultivars at the different planting density and fertility levels were tested and their inheritance mode was studied. The anther length of a spikelet on a secondary panicle branch was longer than the one of a spikelet on a primary panicle branch. In the cultivar Z97B, both the anther and the pistil length were increased slightly along the increased plant-ing spacings, But, in the cultivar IR43 no general tendency was observed. The fertilizer levels applied n the field did not affect both the anther and pistil length of a given cultivar. In a cross of IR56/IR8, the anther length showed continuous variation with longer anther being recessive in the F2 population. While, the pistil length showed a continuous variation with longer pistil being over-dominance. In all of the crosses which IR56 involved, the general and specific combining abilities were high for both the anther and pistil length. The broad sense heritability for anther length was 0.46, and for pistil length was 0.88. The correlation coefficients of anther length and pistil length were 0.33 for phenotypic and 0.44 for geno-typic.

• Korean Journal of Plant Resources
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• v.11 no.2
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• pp.119-123
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• 1998

Effects of elevated CO2 and temperature on nitrogen (N) uptake , leaf N concentration, N partitioning , N use efficiency (NUE) and grain yield of pot and field grown rice (Oryza sativa. L.cv. Chukwangbyeo) under canopy-like conditions were studied over three years. Rice plants were grown in pots and in the field in temperature gradient chambers containing either ambient(350ppm) or elevated CO2 concentrations (690 or 650ppm) in conbination with either four or seven temperature regimes ranging form ambient temperature(AT) to AT plus 3$^{\circ}C$. There were three N supplies 94g or 6g m-2 to 20g or 48g m-2.Elevated CO2 increased N uptake in field-grown rice ; the magnitude of this effect was thelargest (+15%) at the highest N level. However, in pot-grown rice, N uptake was suppressed with the effect was the largest at high N levels. Leaf N concentration declined at elevated CO2 mainly due to a decrease in N partitiioning to the leaf blades. Air temperature had little effect on the N parameters mentioned previously, wherease NUE for spikelet production declined rapidly with increased temperature irrespective of CO2 concentration. The response of the biomass to elevated CO2 varied with N level, with the greatest response at 20g N m-2 (+30%) . At AT, where high temperature-induced sterility was generally not observed, elevated CO2 increased yield. However, the magnitude of this effect varied greatly (2-39%) with N level, and was mainly dependent on the magnitude of the increase in spikelet number.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.1
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• pp.66-72
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• 2006

Spikelet proteins expressed at the young microspore stage in rice were separated and analysed by two-dimensional polyacrylamide gel electrophoresis (2DE). The separated proteins were electro blotted onto a polyvinylidene difluoride (PVDF) membrane, and 50 proteins were analyzed by a gas-phase protein sequencer. The N-terminal amino acid sequences of 20 out of 50 proteins were determined. N-terminal regions of the remaining proteins could not be sequenced because of blocking. The internal amino acid sequences of proteins were determined by sequence analysis of peptides obtained by the Cleveland peptide mapping method. Results revealed the presence of the photosynthetic apparatus at rice young microspore stage. Major proteins identified in this study could be used as a marker for various studies on physiological stresses.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.64 no.3
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• pp.213-224
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• 2019

There is an increasing frequency in the occurrence of abnormal weather phenomena such as sharp increases and decreases in temperature. Under these weather conditions, the heading time of rice changes unexpectedly, which poses problems in agriculture. Therefore, we investigated the effect of temperature on the heading response at different growth stages in rice. During the period from transplanting to heading, the plants were subjected to different temperature treatments, each for a 9-day period, to observe the heading response. For the heading date analysis, "heading date" was defined as the number of days from transplanting to the appearance of the first spikelet. We found that the influence of temperature increased in the order of rooting stage, followed by meiosis, early tillering, spikelet differentiation, and panicle initiation stage in all ecological types and cultivars. In particular, unlike the results reported previously, the effect of temperature on heading during the photo-sensitive period was very small. Meanwhile, the influence of temperature on vegetative growth response at different growth stages was not consistent with heading response. These results can be used as basic data for predicting the variation in heading date owing to temperature variation at each growth stage. In addition, we propose that the concept of day length should be included in determining the influence of temperature on the photo-sensitive period.

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.303-303
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• 2022

The purpose of this study was to evaluate agronomic characteristics and identify the useful traits to utilize the wheat genetic resources for breeding programs by understanding the phenotypic variation among germplasm through multivariate analysis. In this study, a total of 394 wheat accessions were characterized for 15 agronomic traits using the National Agrobiodiversity Center (NAC) descriptor list, of which 31 accessions from 6 species and 363 unidentified accession (Triticum spp.) available at the NAC, Rural Development Administration (RDA), Korea. Growth characteristics such as leaf width, culm length, spike length, spikelet length, solid stemmed, days to heading, days to maturity, grain-filing period, and also seed characteristics such as width, height, area, perimeter, circle, solidity, and germination percent were studied. Among the 15 agronomic characteristics, the germination percent showed the smallest variation between resources (CV = 0.4%), and the spikelet length (CV = 66.5%) showed the highest variation. A strong positive correlation was found between seed traits such as seed height and seed area (r = 0.90), seed height and seed perimeter (r = 0.87) and seed length and width (r = 0.80). Principal component analysis (PCA) was conducted and the first five principal components comprised 76.7% of the total variance. Among the first five PCs, PCI accounted for 28.5% and PC2 for 20.0%. Wheat resources (394) were classified into four clusters based on cluster analysis, consisting of 215 resources(I), 117 resources(II), 48 resources(III), and 14 resources(IV). Among the clusters, the resources belonging to Cluster III showed the lowest seed width, height, area, and perimeter characteristics compared to other clusters. The wheat resources belonging to cluster IV had small seed width and low germination percent, but took longer to form heads and mature than resources in other clusters. These results will serve as the basis for further genetic diversity studies, and important agronomic characteristics will be used for improving wheat, including developing high-yielding and resistant varieties to biotic and abiotic stresses via breeding programs.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.58 no.4
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• pp.353-361
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• 2013

The time of panicle initiation change by transplanting date, and this change is affected by heading ecotype and seedling age. So we assessed the variations of panicle initiation, spikelet differentiation and heading date affected by transplanting dates, rice cultivars and seedling ages. And we compared the growth durations and meterological factors between chief growth stages. The differences of growth duration from transplanting date to spikelet differentiation by seedling age were 1~3 days in all transplanting of Unkwang, but it increased to 4 days in Hwayeong transplanting on May 1 and June 30, and Nampyeong transplanting on June 30. The growth durations from panicle initiation to heading of Unkwang and Hwayeong increased until transplanting time by May 31, and decreased thereafter. The growth durations of Nampyeong increased in transplanting on May 16 and May 31. In each transplanting, mean temperature of 30 days after heading was highest in early transplanting, but sunshine hours in the period were highest in transplanting on June 30 in Unkwang, in transplanting on June 15 in Hwayeong, and higher in transplanting on May 31 and June 15 in Nampyeong. The growth duration between spikelet differentiation and heading showed variation according to rice cultivars and transplanting date, Those were 22~26 days in Unkwang, 21~27 days in Hwayeong and 21~28 days in Nampyeong.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.36 no.5
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• pp.394-406
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• 1991

It was proved that cold tolerance of rice plants at the young microspore stage was affected by water temperature and nitrogen application from the spikelet differentiation stage to the young microspore stage, and this mechanism could be explained in the point of view of pollen developmental physiology. The cold tolerance of rice plants at the young microspore stage was severely affected by water temperature (Previous water temperature) and nitrogen application(Previous nitrogen application) from the spikelet differentiation stage to the spikelet differentiation stage. Although the duration is only 10 days or so from the spikelet differentiation stage to the young microspore stage, these days are very important period to confirm the cold tolerance of rice plants at the young microspore stage. The higher previous water temperature up to $25^{\circ}C$ and the deeper previous water depth up to 10cm caused the more cold tolerance of rice plants. Water irrigation of 10cm before the cretical stage showed lower cool injury than that of water irrigation of 20cm during the critical stage. The preventive effect of cool injury by combined treatment of the deep water irrigation before and during the critical stage was not additive but synergistic. The cold tolerance of rice plants grown in previous heavy nitrogen level was rapidly decreased when nitrogen content of leaf blade at the young microspore stage was excessive over the critical nitrogen level. Nitrogen content of leaf blade at the changing point of cold tolerance was estimated as about 3.5% for Japonica cultivars and about 2.5% for Indica x Japonica cultuvars. It is considered that these critical nitrogen contents of leaf blade can be used as a index of the safe critical nitrogen level for the preventive practices to cool injury. It was summarized that increase of engorged pollens per anther by high previous water temperature resulted from the increase of number of differentiated microspores per anther, otherwise, the increase of engorged pollens by the decrease of previous nitrogen level was caused by the decrease of the number of aborted microspores per anther.

• Proceedings of the Korean Society of Plant Biotechnology Conference
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• 2005.04a
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• pp.73-73
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• 2005

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.4
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• pp.348-355
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• 2006

Phenotypes of panicle, hull and seed of mutant rice (Oryza sativa L.) were characterized. Panicle mutants were classified in 4 groups with their internode length of main rachis, primary rachis, secondary rachis and pedicel. Hull and seed mutants were grouped into 12 based on their mutant characters in shape, size and color of seeds. These natural and spontaneous mutant collections showed distinct phenotypes to wild type rice. This might be useful for the identification of the functions of genetic factors in the Mendelian inheritance.

• Korean Journal of Plant Taxonomy
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• v.52 no.4
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• pp.214-218
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• 2022

Eleocharis R. Br. (Cyperaceae) is characterized by unbranched culms, one terminal spikelet, bisexual flowers, and bristly perianths, occurring mainly in circumboreal marshes and wetlands. There are about 250 species worldwide, and 15 taxa in Korea have been recognized. Chromosomes in Cyperaceae are known to be holocentric, missing constricted centromeres during cell division. For the first time, we report the chromosome counts of Eleocharis from Korean populations of E. attenuata f. laeviseta (Nakai) H. Hara (2n = 20); E. parvula (Roem. & Schult.) Link ex Bluff, Nees & Schauer (2n = 10); E. ussuriensis Zinserl. (2n = 16); and E. valleculosa var. setosa Ohwi (2n = 16). The populations exhibit variations in their chromosome sizes from ca.1.7 ㎛ to ca. 6 ㎛, categorized as gradient and bimodal karyotypes. The karyotypes observed are congruent with previous phylogenetic groups proposed. To clarify the traditional and phylogenetic classification of Korean Eleocharis, further taxonomic and chromosomal investigations with additional taxon sampling efforts are required.